docker-compose.yml

services:
  mc:
    image: itzg/minecraft-server
    tty: true
    stdin_open: true
    ports:
      - "25565:25565"
    environment:
      INIT_MEMORY: 1G
      MAX_MEMORY: 4G
      EULA: "TRUE"
      TYPE: "FABRIC"
      VERSION: "1.20.4"
      DIFFICULTY: "hard"
      FORCE_GAMEMODE: true
      MODE: "survival"
      PVP: true
      SERVER_NAME: "Maiden"
      ENABLE_WHITELIST: true
      WHITELIST_FILE: "/data/whitelist.json"
    volumes:
      # attach the relative directory 'data' to the container's /data path
      - ./data:/data
  backups:
    image: itzg/mc-backup
    environment:
      BACKUP_INTERVAL: "8h"
      RCON_HOST: mc
      PRE_BACKUP_SCRIPT: |
        echo "Before backup!"
        echo "Also before backup from $$RCON_HOST to $$DEST_DIR"
      POST_BACKUP_SCRIPT_FILE: /post-backup.sh
    volumes:
      # mount the same volume used by server, but read-only
      - ./data:/data:ro
      # use a host attached directory so that it in turn can be backed up
      # to external/cloud storage
      - ./backups:/backups
      - ./post-backup.sh:/post-backup.sh:ro

post-backup.sh

#!/bin/sh
echo "Backup from $RCON_HOST to $DEST_DIR finished"